Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proteoglycans were extracted from nuclease-digested sonicates of 10(9) rat basophilic leukemia (RBL-1) cells by the addition of 0.1% Zwittergent 3-12 and 4 M guanidine hydrochloride and were purified by sequential CsCl density gradient ultracentrifugation, DE52 ion exchange chromatography, and Sepharose CL-6B gel filtration chromatography under dissociative conditions. Between 0.3 and 0.8 mg of purified proteoglycan was obtained from approximately 1 g initial dry weight of cells with a purification of 200-800-fold. The purified proteoglycans had a hydrodynamic size range of Mr 100,000-150,000 and were resistant to degradation by a molar excess of trypsin, alpha-chymotrypsin, Pronase, papain, chymopapain, collagenase, and elastase. Amino acid analysis of the peptide core revealed a preponderance of Gly (35.4%), Ser (22.5%), and Ala (9.5%). Approximately 70% of the glycosaminoglycan side chains of RBL-1 proteoglycans were digested by chondroitinase ABC and 27% were hydrolyzed by treatment with nitrous acid. Sephadex G-200 chromatography of glycosaminoglycans liberated from the intact molecule by beta-elimination demonstrated that both the nitrous acid-resistant (chondroitin sulfate) and the chondroitinase ABC-resistant (heparin/heparan sulfate) glycosaminoglycans were of approximately Mr 12,000. Analysis of the chondroitin sulfate disaccharides in different preparations by amino-cyano high performance liquid chromatography revealed that 9-29% were the unusual disulfated disaccharide chondroitin sulfate di-B (IdUA-2-SO4----GalNAc-4-SO4); the remainder were the monosulfated disaccharide GlcUA----GalNAc-4-SO4. Subpopulations of proteoglycans in one preparation were separated by anion exchange high performance liquid chromatography and were found to contain chondroitin sulfate glycosaminoglycans whose disulfated disaccharides ranged from 9-49%. However, no segregation of subpopulations without both chondroitin sulfate di-B and heparin/heparan sulfate glycosaminoglycans was achieved, suggesting that RBL-1 proteoglycans might be hybrids containing both classes of glycosaminoglycans. Sepharose CL-6B chromatography of RBL-1 proteoglycans digested with chondroitinase ABC revealed that less than 7% of the molecules in the digest chromatographed with the hydrodynamic size of undigested proteoglycans, suggesting that at most 7% of the proteoglycans lack chondroitin sulfate glycosaminoglycans.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Purification and characterization of protease-resistant secretory granule proteoglycans containing chondroitin sulfate di-B and heparin-like glycosaminoglycans from rat basophilic leukemia cells. 241 30

Novel antibodies were raised against a synthetic NH2-terminal myristoyl glycine moiety which is characteristic of N-myristoyl-proteins. Antisera raised against N-myristoyl-Gly-hemocyanin reacted with N-myristoyl-Gly-[125I]albumin. The immunoreaction was competed for by albumin conjugated with N-myristoyl-glycine, while underivatized albumin had no effect. Of the [3H]myristate-labeled proteins detected, pp60v-src, which is a transforming protein of Rous sarcoma virus, and p19gag and p17gag, which are core proteins in the human T-cell leukemia virus and the human immunodeficiency virus, were identified as N-myristoylated proteins by the radioimmunoprecipitation analyses with the antibody.
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PMID:Antibodies to an NH2-terminal myristoyl glycine moiety can detect NH2-terminal myristoylated proteins in the retrovirus-infected cells. 254 72

DAP-IV activity (Gly-Pro-MCA hydrolysis, pH 7.8) was found in lysates of peripheral blood lymphocytes of patients with T- and B-cell forms of malignant lymphoproliferative diseases. The highest DAP-IV activity was seen in the cells of patients with a rare variant of T-cell lymphocytic leukemia (T-CLL); these cells expressed simultaneously the antigens of T helpers and T suppressors (Th and Ts) (OKT4+ and OKT8+). The DAP-IV activity about ten times less was found in the pathological cells with a phenotype of mature Th (Sezary disease), as well as in the cells expressing antigens of both Ts and natural killers (a rare variant of T-CLL). The same activity was also found in Ts (T gamma-lymphocytosis). The data obtained show that the differences in DAP-IV expression are connected with the differentiation step rather than with the belonging to a particular subpopulation of T-cells. DAP-IV activity, which was somewhat lower than that of T-cells, was found in B-lymphocytes of patients with B-CLL, hair-cellular leukemia, and non-Hodgkin's lymphoma. No correlation of DAP-IV activity with the level of E-cellular differentiation was observed.
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PMID:[Dipeptidyl aminopeptidase-IV in lymphocytes of patients with lymphoproliferative diseases]. 257 81

The full-length provirus of human T-cell leukemia virus type I (HTLV-I) was isolated from MT-2, a lymphoid cell line producing HTLV-I. In transfected cells, structural proteins of HTLV-I, the gag and env products, were formed and processed in the same manner as observed in MT-2 cells. The nucleotide sequence was determined for a region between the gag and pol genes of the proviral DNA clone containing an open-reading frame. The deduced amino acid sequences show that this open-reading frame encodes a putative HTLV-I protease. The protease gene (pro) of HTLV-I was investigated using a vaccinia virus expression vector. Processing of 53k gag precursor polyprotein into mature p19, p24, and p15 gag structural proteins was detectable with a recombinant plasmid harboring the entire gag- and protease-coding sequence. We demonstrated that the protease processed the gag precursor polyprotein in a trans-action. A change in the sequence Asp(64)-Thr-Gly, the catalytic core sequence among aspartyl proteases, to Gly-Thr-Gly was shown to abolish correct processing, suggesting that HTLV-I protease may belong to the aspartyl protease group. The 76k gag-pro precursor polyprotein was identified, implying that a cis-acting function of HTLV-I protease may be necessary to trigger the initial cleavage event for its own release from a precursor protein, followed by the release of p53 gag precursor protein. The p53 gag precursor protein is then processed by the trans-action of the released protease to form p19, p24, and p15.
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PMID:Identification of HTLV-I gag protease and its sequential processing of the gag gene product. 266 87

Retrovirus protease is an enzyme that cleaves gag and gag-pol precursor polyproteins into the functional proteins of mature virus particles. The correct processing of precursor polyproteins is necessary for the infectivity of virus particles: in vitro mutagenesis which introduces deletions into the murine leukaemia virus genome produces a protease-defective virus of immature core form and lacking infectivity. A therapeutic drug effective against disease caused by retrovirus proliferation could likewise interfere with virus maturation. The primary structure has so far been determined for the protease of avian myeloblastosis virus, and of murine, feline and bovine leukaemia viruses. Amino acid sequencing of the retrovirus proteases, either after their purification or from prediction from the nucleotide sequence, shows that they possess the Asp-Thr-Gly sequence characteristic of the aspartyl proteinases. In this report we show that retrovirus proteases belong to the aspartyl proteinase group and demonstrate an inhibition by the aspartyl proteinase-specific inhibitor, pepstatin A, on the activity of bovine leukaemia, Moloney murine leukaemia and human T-cell leukaemia virus proteases.
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PMID:Inhibition of retroviral protease activity by an aspartyl proteinase inhibitor. 282 9

In human lymphocytes three dipeptidyl peptidases were discovered in our laboratory. For a correct demonstration of activities of these enzymes discriminating substrates must be used. Dipeptidyl peptidase IV (DPP IV) is revealed with Gly-Pro-4-methoxy-2-naphthylamide (Gly-Pro-MNA) and Fast Blue B (FBB). It is present in the surface membrane of about 40% lymphocytes of the peripheral blood. Only T-lymphocytes bear the reaction. Reacting lymphocytes belong predominantly to OKT4+ subset. Some OKT8+ lymphocytes also react. With more sensitive substrates (Lys-Pro-MNA, Phe-Pro-MNA and Ala-Pro-MNA) a co-reaction of DPP II was demonstrated "in situ" and in zymograms. In haemoblastoses a positive reaction in cells indicates their derivation from the T-lineage of lymphocytes. A negative reaction does not exclude a T-cell malignancy, however. A decreased number of DPP IV positive lymphocytes in the peripheral blood indicates a diminished immunocompetent potential of T-cells, e.g. immunodeficiency in patients with malignant lymphoma, gastric and colocrectal carcinoma, AIDS, etc. DPP II demonstrated with Lys-Ala-MNA occurs in about 60% of lymphocytes belonging to T and B subsets. It is localized in lysosomes. Although Lys-Pro-MNA is a more sensitive substrate a co-reaction of DPP IV must always be considered. Patients with chronic B-lymphocytic leukaemia displaying a high number of DPP II+ cells usually have a worse prognosis. DPP I assessed with Gly-Pro-MNA and nitrosalicylaldehyde occurs in about 20% of T and B lymphocytes. The number of positively reacting cells increases after corticosteroid therapy. The influence of the treatment on the activity can be shown very well in histograms of DPP I activity measured by computer-assisted microfluorometry.
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PMID:Dipeptidyl peptidases of human lymphocytes. 290 80

The plasma membrane of murine erythro-leukemia (MEL) cells contains a 140-kD protein that binds specifically to fibronectin. A 125I-labeled 140-kD protein from surface-labeled uninduced MEL cells was specifically bound by an affinity matrix that contained the 115-kD cell binding fragment of fibronectin, and specifically eluted by a synthetic peptide that has cell attachment-promoting activity. The loss of this protein during erythroid differentiation was correlated with loss of cellular adhesion to fibronectin. Both MEL cells and reticulocytes attached to the same site on fibronectin as do fibroblasts since adhesion of erythroid cells to fibronectin was specifically blocked by a monoclonal antibody directed against the cell-binding fragment of fibronectin and by a synthetic peptide containing the Arg-Gly-Asp-Ser sequence found in the cell-binding fragment of fibronectin. Erythroid cells attached specifically to surfaces coated either with the 115-kD cell-binding fragment of fibronectin or with the synthetic peptide-albumin complex. Thus, the erythroid 140-kD protein exhibits several properties in common with those described for the fibronectin receptor of fibroblasts. We propose that loss or modification of this protein at the cell surface is responsible for the loss of cellular adhesion to fibronectin during erythroid differentiation.
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PMID:The fibronectin receptor on mammalian erythroid precursor cells: characterization and developmental regulation. 293 41

We have purified two low-molecular-weight polypeptides from the Prague C strain of Rous sarcoma virus and have identified these as products of the gag precursor Pr76 by protein sequencing and by amino acid analysis. Both polypeptides are derived from a stretch of 22 amino acids within Pr76 that separates p19 and p10. We refer to this region as p2. Together the two cleavage products form the entire p2 region. The junctions of p19 with the amino-terminal fragment of p2 and of p10 with the carboxy-terminal fragment of p2 define two new processing sites within the gag precursor, Tyr-155-His-156 and Gly-177-Ser-178. Both polypeptides are major cleavage products of Pr76 that occur in Prague C Rous sarcoma virus at an estimated 1,000 copies per virion. They also are prominent components of avian myeloblastosis virus. The combination of gel filtration and reverse-phase high-pressure liquid chromatography, which was used for the isolation of the two fragments of p2, resolved over a dozen other low-molecular-weight polypeptides from avian sarcoma and leukemia viruses that previously were undetected. This technique thus should serve as a useful procedure for further characterization of viral components.
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PMID:Structure and processing of the p2 region of avian sarcoma and leukemia virus gag precursor polyproteins. 300 58

The transport of glycine and L-lysine into murine P388 leukemia cells has been examined. Glycine transport appears to be shared by both systems A and ASC in P388 cells. Glycine transport is Na+-dependent and is effectively blocked by alpha-(methylamino)isobutyric acid, threonine and alanine but only a marginal reduction in transport is seen with 100-fold excess cold 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid. System gly is not expressed in P388 cells. Lysine is largely transported by a Na+-independent, pH-insensitive system with a Km of 0.079 mM. Lysine transport is relatively unaffected by the addition of 100-fold excess cold alpha-(methylamino)isobutyric acid, 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid and the anionic amino acids, L-glutamate and L-aspartate. A partial inhibition of lysine transport was observed with L-threonine and L-leucine while L-arginine and L-histidine radically decreased lysine transport. Lysine appears to be transported by a system similar to the system y+ seen in cultured human fibroblasts, Ehrlich ascites cells, and hepatoma cell lines.
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PMID:Further studies on amino acid transport in murine P388 leukemia cells in vitro. Presence of system y+. 310 85

N-Myristoyl (N-Myr-) glycinal (aminoacetoaldehyde, GO) diethylacetal (A), which is abbreviated as N-Myr-GOA, and other N-Myr-compounds (N-Myr-Gly-GOA, N-Myr-Gly-Gly-GOA, and N-Myr-Gly-Gly-Gly-GOA) were newly synthesized and then employed for NH2-terminal antimyristoylation of structure proteins in the human T-cell leukemia virus (HTLV-I) and the human immunodeficiency virus (HIV). The protein myristoylation of structure proteins p19gag, of HTLV-I, and p17gag, of HIV, was determined separately, using radiolabeled myristic acid, in vitro. The radiolabeled proteins, after immunoprecipitation with an antiserum to adult T-cell leukemia (ATL) or the anti-p17gag monoclonal antibody of HIV, were identified as p19gag of HTLV-I and p17gag of HIV by fluorography after SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The protein myristoylation was resistant to NH2OH-treatment. Of the N-Myr-compounds tested, N-Myr-GOA remarkably prevented the myristoylation of p19gag and p17gag, but N-Myr-Gly-Gly-GOA and N-Myr-Gly-Gly-Gly-GOA did not.
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PMID:Antimyristoylation of gag proteins in human T-cell leukemia and human immunodeficiency viruses with N-myristoyl glycinal diethylacetal. 326 65


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